sub bind_hash {
    my $table = shift;
    my %results;
    my $sql = do {
        local $" = ", ";
        "SELECT @_ FROM $table";
    };

    my $sth = $dbh->prepare($sql);
    $sth->execute();
    $sth->bind_columns(map { \$results{$_} } @_);

    return (\%results, sub { $sth->fetch() });
}

# ... later:

my ($res, $fetch) = bind_hash users => qw(name email);
while ($fetch->()) {
    print "$res->{name} >$res->{email}>\n";
}